Differential



D. E. SCHOTT Jan. 6, 1953 DIFFERENTIAL 5 Sheets-Sheet 1 Filed Dec. 1 1951 \NV NTOR mm 5 mm" D. E. SCHOTT DIFFERENTIAL Jan. 6, 1953 s snee s-sheet 2 Filed Dec. 1, 1951 INV OR Jan. 6, 1953 D. E. SCHOTT 2,624,213

DIFFERENTIAL Filed Dec. 1, 1951 5 Sheets-Sheet 4 W4 5". @1229 fiw MZMM Q ATTORNEYS D. E. SCHOTT Jan. 6, 1953 DIFFERENTIAL 5 Sheets-Sheet 5 Filed Dec. 1 1951 ATTORNEYS Patented Jan. 6, 1953 UNITED STATES PATENT ()FFICE 2,624,213 DIFFERENTIAL Donald E. Schott, Flushing, N. Y.

Application December 1,

12 Claims.

This invention relates to torque distributors, commonly referred to as differentials, and is concerned more particularly with a novel differential, which affords numerous advantages over similar devices as heretofore constructed.

The new differential is simple in construction and it is inexpensive to manufacture, because it does not include any gears and can be made without the use of special machinery. It provides a useful torque output on either driven member, independent of the load on the other, and operates in that manner in both directions of rotation. Also, it provides a free differentiating action, when the direction of power transmission through it is reversed as, for example, in an automobile, which is coasting, with the wheels driving the engine. The differential provides a positive drive at all times without excessive backlash and does not operate as a friction device. All operating stresses occur as radial, tensile, or compressive stresses within the driven members, and such stresses are not transmitted to or carried by bearings, and no thrust loads are produced. In its preferred form, the differential is symmetrical in construction and operation, so that it is dynamically balanced at all positions and speeds.

While the new differential may be used for numerous purposes, it affords special advantages, when employed in automotive vehicles. An embodiment of the differential suitable for such use ill, accordingly, be illustrated and described in detail for purposes of explanation.

The automotive form of the new differential comprises a pair of like driven members connected to the aligned axial shafts of the vehicle and lying spaced apart. The members may have the form of discs, and the opposed faces of the discs are provided with a plurality of intersecting circular grooves. The grooves in the two discs are all of the same radius, and the centers of curvature of the grooves in each disc are equally spaced from and equiangularly spaced about the center of the disc. Each disc is provided with at least two such grooves and may have three or more. As discs with two grooves are suitable for most purposes, that construction is preferred.

A driving member, which is preferably of disc form, lies between the grooved faces of the driven members and has a plurality of angularly spaced radial slots. The number of slots in the driving member is the same as the number of grooves in a driven member or twice the number of grooves, the latter arrangement being preferred. A slide 1951, Serial No. 259,433

is mounted in each slot in the driving member for movement lengthwise of the slot, and each slide has ends projecting at opposite sides of the driving member. Between the driving member and each driven member, there is a set of connectors, one for each slide, and each connector is mounted for rocking movement on the end of a slide and has an arcuate rib entering a groove in the adjacent driven member. The arrangement of the connectors relative to the driven members is such that each slide lying in alignment with aligned intersections of grooves in the two discs engages a pair of connectors, which have ribs entering non-registering grooves in the two driven members. The driving member is driven from a prime mover in any convenient manner and, for this purpose, may carry a gear encircling its periphery. The driven members are connected to the driven shafts, preferably by being provided with hubs splined to the shafts.

For a better understanding of the invention, reference may be made to the accompanying drawings in which:

Fig. l is a longitudinal section through one form of the new differential on the line 1-! of Fig. 2;

Figs. 2, 3, and 4 are transverse sectional views on the lines 2-2, 3-3, and 4-4, respectively, of Fig. 1;

Fig. 5 is an elevational view showing the grooves in one driven member;

7 Fig. 6 is an exploded perspective view of certain parts of the new differential shown in Fig. 1;

Fig. '1 is a diagrammatic elevational view showing the relationship of the grooves in the driven members, when one member has been rotated from the position shown in Fig. 5;

Fig. 8 is a diagrammatic elevational view, showing a driven member having three grooves;

Fig. 9 is a series of diagrams illustrating the operation of the device;

Fig. 10 is a diagram showing the resolution of forces involved in the functioning of the differential;

Fig. 11 is a view similar to Fig. 1 showing a modified form of the differential;

Figs. 12 and 13 are sectional views on the lines 2-4 2, 13-43, respectively, of Fig. 11;

Figs. 14 and 15 are elevational views of the driving member and a driven member, respec tively, of the differential shown in Fig. 11;

Fig. 16 is a view in elevation of one of the connectors of the differential of Fig. -11; and

Fig. 17 is a view, partly in elevation and partly 3 in section, of a slide used in the differential of Fig. 11.

The differential illustrated in Fig. 1 is suitable for use in an automobile having aligned axle shafts 26 within an axle housing shown as made of two parts 2 I, 22, and it includes a pair of driven members 23, 24 of identical construction. The members have the form of discs provided with hubs 23a, 24a splined to respective shafts 253 and a plurality of intersecting circular grooves are formed in the face of each disc. The grooves in the discs are all of the same radius and the centers of curvature of the grooves are equally spaced from and equiangularly spaced about the common axis of the discs. The discs illustrated are provided with two grooves and the centers of curvature of the grooves in a disc are, accordingly, 180 apart and thus lie on a, diameter of the disc at equal distances on opposite sides of the axis thereof. The grooves in the two discs are designated 25, 26, and, when the driven members in the assembled differential lie with the centers of curvature of their grooves on a line and the assembly is viewed from one end, the grooves 25 and 26 of one disc are in registry with the grooves 26 and 25, -respectively,-of the other disc.

The driven members are rotated by a driving member 21, which iscoaxial with the driven members and has the'form of a plate 28 having a cylindrical rim 29. The plate lies between the opposed faces of the discs of the driven members and it is provided with a plurality of angularly spaced radial slots 30. The plate has the same number of slots as the number of grooves in a disc or has twice as many slots as there are grooves, the latter arrangement being preferred. In the construction shown, the plate 28 has four slots 33 spaced 90 apart and the slots are open to each other at the axis of the driving member and terminate short of the rim 29 thereon.

A supporting member 3| of disc form having a hub 31a is mounted with its hub encircling the hub 23a of driven member 23, and a generally similar supportingmember 32 having a hub 32a is mounted with its hub encircling hub Ma of riven member 2 4. Anti-friction bearings 33, 34 are interposed betweenhubs 3m, 32a, respectively, andthe parts 2|, 22 of the axle housing. The member 3| is provided with an offset pe- -riphera1 flange 35b abutting one end of the rim 29 of the driving member, and a bevel ring gear '35 is secured to the flange by screws 36 passing through-the web of the gear and the flange into the adjacent end of the rim 29 on the driving member. The other end of the rim 29 is seated in a peripheral channel in the outer edge of member 32. 7

A slide 31 is mounted in each slot 39 in the driving plate and each slide has the form of a cylindrical pin provided with flats 31a engaging the walls of its slot. The ends of each slide projecton opposite sides of plate 28 of the driving member.

A set of connectors 33 of quadrant form lie between each driven member and the driving member, and each set is made up of a connector for each slide. Each connector is provided on one face with an arcuate rib 38a entering a circular groove in the adjacent driven member, and the other face of the connector is formed with a circular socket 3% receiving a, projecting end of a slide 37. Of the four connectors in a set, two adjacent connectors have ribs entering one groove in the adjacent driven member and the ribs of the other two connectors enter the other groove. The connectors are mounted on the slides in such fashion that each slide, which lies in line with aligned intersections of grooves in the two driven members, is engaged with a pair of connectors mounted for sliding movement in non-registering grooves in the respective members. This arrangement will be understood from Figs. 2 and l, in which the centers of curvature of the grooves in the two drivenmembers are shown as lying on a horizontal line through the common axis of rotation of the members. Slide 370 lies in line with the aligned upper intersections of the grooves in the two members, and connector 38c, mounted on one end of the slide, has a rib entering groove 26 in driven member 23. Connector 38d, mounted on the other end of slide 37:), has a rib entering groove 23 in driven memberM, the grooves 26 in the two members being out of registry with each other.

The driving member of the differential may be rotated by power appliedthereto in any convenient manner as, for example, the driving member may have a rim formed as a pulley and be driven by a belt, or the rim may have sprocket teeth and be driven by a chain. For automotive purposes, power is transmitted; from the propeller shaft of the vehicle to the differential through gearing, including the driving gear 35. 1

In thebperationbf the differential, gear. 35, driving member 2?, and the supporting members 3|, 32 rotate as a unitabout the common axis of shafts In this rotation ofthe driving mem ber, it carries the slides ii'l with it, and those slides, such as slide 3lc, which lie in line with aligned intersections of grooves in the driven members, apply power to the driven member tending to rotate them. If both driven members are unrestrained, the members rotate with the slides and connectors and the latter remain stationary in their slots and grooves, respectively. If one driven member is restrained, adifferentiating action takes place, which is made clearin Fig.9. r

In. the eight diagrams in Fig. 9, the circular grooves of the two members are illustrated as they would appear, if viewed from the outer end of member 24. The grooves in member 2 are shown in full lines and designated 25a, Zficgyand the grooves in member 23 are shown in dotted 'lines designated 25b, 2st, The radial slots in the and the slides 31 are indicated by solid circles, two of the slides lying 180 apart being marked A and B. V

In Fig. 9a, the two driven members are shown with the centers of curvaturesof their grooves lying on a horizontal line, so that groove 25a in member. 2 3 is in registrywith groove '2 ti) in member 23, and groove 25a in member 24 is in registry withgroove 25b in member 23. When the driven members are in the positions shown, the. driving member lies with two of its slots iii) extending horizontallyv and the othertwo extending vertically and the slides A and Blie within vertical slots and in line, respectively, with'aligned upper and lower intersections'of the grooves in the two discs. The connector between slide-A and driven member 24 has a rib entering groove 25a inmember 24 and the connecting element between the slide and drivenmem'ber 23 has a rib entering groove 2% in member 23, the two grooves being out of registry. Similarly, slide 13 is in engage ment with connectors having ribs in non-registeringgrooves in the driven members. I

Fig. 9b shows What occurs, when the driving driven member are indicated by broken lines 33 member is rotated through. an angle, of 45 counterclockwise, while driven member '24 remains at rest. In such rotational movement, the slide A moves through an angle of 45 with the driving member and, at the same time, the connector on the end of the slide, which has a rib entering groove 26a in driven member 24 remaining at rest, moves along groove 25a and the slide is caused to move inwardly along its slot. During this movement of slide A, the connector between the slide and member 23 has moved along groove 26b of member 23 and has caused member 23 to move counterclockwise through an angle of 90. Slide 13 has moved in the same manner as slide A and assisted in the rotation of member 23. In the new position of member 23, the. centers of curvature of its grooves lie on a vertical line.

Fig. 9c shows the relation of the two driven members, when the driving member has moved counterclockwise through an angle of 90 from its original position. In this condition of the driven members, their centers of curvature lie on a horizontal line and, whilethe driving membar has passed through 90", driven member 23 has been rotated through 180. At the same time, the slides A and B have moved inwardly in their slots to their. inmost positions.

When the driving member moves through another 45, as shown in Fig. 9d, the driven member 23 is moved through another 90 and, when the driving member has traveled through 180, as shown in Fig. Be, the driven member 23 has been rotated through one complete turn. The two driven members 23, 24 then lie with their grooves in the same relative positions as in Fig. 9a, but slides A and B now lie in line, respectively, with the lower and upper intersections of the grooves in the two members. Figs. 9 g, and it show the positions of the driving and driven members after further successive advances of the driving memher through angles of 45 and, when the driving member is advanced 45 beyond the position shown in Fig. 971., the parts assume the positions shown in Fig. 9a, and slides A and B again lie in line, respectively, with the aligned upper and lower intersections of the grooves in the two I members. Accordingly, when driven member 24 is wholly restrained and the driving member r0- tates through 360, driven member 23 is rotated through two complete turns or 720.

The form of the differential shown in Figs. 11-17, inc., comprises a pair of like driven members 39, 40 having the form of discs provided with hubs 39a, 40a splined to respective aligned axle shafts 20', 20 within an axle housing ma'deof two parts 2 l 22'. The opposed faces of the discs are provided with a plurality of intersecting cir cular grooves 4|, 42, and the grooves in the dis-cs are all of the same radius and the centers of curvature of the grooves are equally spacedfrom and equiangularlyspaced about the common axis of the discs. An anti-friction bearing 33' lies between hub 33a of driven member 39 and axle housing 2|, and a similar anti-friction bearing 34' lies between hub 43 of driven member 40 and axle housing 22'.

A driving member 43 lies between the driven members and it has the form of a disc provided with a plurality of radial slots 44. An axial stud 45 projects from each face of the driving member and is received in a central socket 46 in the adja-cent driven member. A ring gear 41, having an internal flange 41a, is mounted to encircle the driving member with, the flange lying against one face of the driving member, and the gear is sethrough. .flange 41a. and openings cured to the driving member by bolts 48 passing through the driving member. i

A slide. 49, which. is similar to slide .31, is mounted in each radial slot 44 of the drivin member and has cylindrical ends projecting beyond opposite faces of the driving member. A connector 50, which is generally of quadrant form, is mounted for rocking movement on each end of each slide, and each connector has a curved rib 50a, which entersone of the grooves 41, 42 in the opposed face ofthe adjacent driven member. .Of the four connecting elements between the driving memberv and each driven member, two adjacent elements have ribs enterin the .samegroove in the driven member, and the otherv two have ribs entering. the other groove in the driven member. A slide, such as. slide 49 a.(Fig. 12),. which lies in line with aligned intersectionsof the grooves in the. two driven members, engages a pair of connectors having ribs mounted for sliding movement in non-registering grooves in the respectivev members, as will be apparent from Figs. 12 and 1?. Thus, the: connector 5| mounted on slide 43a. has a. rib, which enters groove 42 in member 39, whereas the connector 52 has a rib entering groove. 42 in driven element 40.. As viewedfrom either end of the assembly,- grooves .42 have their centers on a horizontal line through the axis of the. assembly but are out of registry. Theslide 49a lies in registry with the aligned upper intersections of the grooves in the two driven members, and the connecting elements mounted on slide 491), which lies in line with the aligned lower intersections of the grooves in the two driven members, likewise engages a pair of connectors having ribs mounted. in non-registering grooves in the two driven members.

The form of the differential shown in Figs. 11-17, inc., is simpler than that shown in Fig. l, in the respect that the Fig. 11 form does not require supporting members corresponding to members 3|, 32, and the driving member 43 is of simpler construction than member 21. The Fig. 11 form of the differential functions in the same manner as that shown in Fig. 1 and. provides a differentiating action, as explained in connection with'Fig. 9. In the device of Fig. 11, the connectors are formed with their ribs lying close to the curved edges of the connectors and the socket in each connector for receiving the projecting end of the slide is of relatively large diameter. The slides 49 used in the Fig. 11 device are generally similar to slides 31 but have cylindrical ends of greater diameter than the corresponding ends of slides 31.

The diagram, Fig. 10, illustrates the resolution of forces effective in the new differential as shown in Fig. 1 to cause rotation of the driven members, when one is free to rotate and the other is restrained. In the diagram, the circles C1, C2 represent aligned pairs of intersecting grooves lying at the points Cut and C20 respectively, which are shown as lying on a horizontal line through the common axis of rotation A of the driven members. The lines L1 and L2, passing through the centers of the grooves and the upper point of intersection I of the grooves, then define an angle a. The lines L3, L4 are tangent to grooves C1, C2, respectively, at the point Land the angle between lines L3, L4 is angle a and is bisected into two angles 3 byline L5, whichis tangent at I to an imaginary circle having its center at A.

The line Ls, .passing through .point v.Igmakes an angleewithlineliz, thevalue ofanglerfi being.

.such that tan 0 equals the co-efiicientfiorifriction .between the surfacesofztheigrooves and the libSiOf the connectors .sli'dinginithe grooves. The iangle between line .Ls and 'line:Ls.;isthe difference: between .angle ,8 'andangle-"eiand may be'referred to asangle 5- 0.

Fig. 10, the line :Tixrepresents'the torque input applied tonaislide at *point I and: tending to tcause'rotation of the assembly made up of the slidefth connectors, "the drivenme'mbers, etc. The line L7 passing through-point I ma'kes an ianglexfi l ewith the. vertical lineiLapassing through:- points I and A. Line L9 .is normal to line Tiat the 'originz thereof and intersectsrline In at :pointiP. :Since' the slide, to which-the force Ti-is applied at. point I, is engaged with aipair of' connectors sliding in non-registering grooves in the two driven members, the force Tixisexertedwith a wedging action andonlyhalflthe length of line L9 isto be consideredin determining the vertical'resultant RofzforcefIli. ..Accordingly, the line L10. has been drawn to lbisect line L9 and lies parallel to line Ti. Th'evertical resultant is then the lengthof line Labetween point I and the point PI of intersection of. lines Ls and-L10. Aspart of the resultant :R-is employed in overcoming friction, the net'resultant Rv :equal to I and'PZ; the point P2 lying spaced from pointPl a distance d,"which' is equal to the input force Ti multiplied by the coefficientiof friction, that is, tan 0. A line Ln drawn'fromipoint PZ and making an angle 'of 18-0with liheLa intersects the continuation of lineTz at point P3, and the line Tr between points I iandP3 represents the force tending to cause rotation of: the driven member free to rotate. The force tending to cause rotation of the driven member, which isrestrained, is the difference between'Ti and Tr.

The mathematical formulae for determining the valuesiotTr'and Ts are asfollows:

Applyingv the formulae to aspeoiiic'd'ifferential, inflwhich angle (1:209, angle/3:10 the. coefilcient offri'c'ti'on of the ribs or. the connectors sliding in the grooves is assumed toequal .G87,..so..that angle 0=5, and T2 is assumed to equal unityrthe value of R, as determined by Formulad, equals 1.83. The net vertical resultant R1 tending. to efor the force Ts tending to cause rotation of the restrained driven member is"5.6 times the force Tr tending to cause rotation of the driven member iree'to rotate.

It can be determined by calculationfrom the the length of line Ls .betweenpoints iormulaeit'hat, withagiven coeficienttof friction and correspondingnngle '6, ivariations. inzanglez a. produce 'diiierent .zaverage proportions: of the input torque available for aLbSOI'ptiOXI bYTthQ-TE- strained. and unrestrained driven t members, respectively. 'When angle a has .a'"value of about O0, the. proportions. of. input torque available for absorption byzthe two members i is :approximately the same; disregarding: frictional 105595;..30 that the new 'differential,- in. whichisuchan. angle a is employed, operates in thesame manner. as. a conventional differential. .It will'alsobeevident from theformulae thatan'gle [i must always: equal or exceed Gland. thus angle w .must'a'lwaysrequal or exceed 26. 'If' angle fiequals mall the inputtorque is applied tothe restrained 'drivenwmembenand none tothe unrestrainedidriven member. iAs itis desirable, particularly inautomotive usegthatthe part of the input torque tendingto-causerotation of the restrained drh/en membcube-substantially greater than available to cause rotation of the unrestrained driven member, the difierential is best constructed-with angle rt-greate'r than but approaching angle 20 as olosely'as practical'structural considerations permit.

The relative average proportions of the torque absorbed by the driven members can be influenced further by varyingthe.locatiOnOfthe pivot centers of the slides in their connectors, either inwardly or outwardly radially'relative to the'ribs on the connectors, which enter-the'grooves in the driven members. Moving the pivot centers in- Wardly has the same effect as decreasing angl a, while moving the pivot centers outwardly has the opposite effect.

In the form of the differential shown in Figs. l-6, incl, the. center of the pivot socket in each connector is intersected by the'center line of the arc of the rib on that connector and-the diagram Fig. IOapplies to that construction. In the form of the differential shown in Figs- 1147, incl, the center of the pivot socket in each connectorlies inwardly radially from the center line of the-arc of therib. In this construction, thevalue of the angle B'for calculating R- in Formula l is determined as follows. An arc of a radius equal to the distance of the pivot socket onconnector from the center of curvature of the groove entered by the ribofthat connector is-drawn on' Fig. 10 about that center of-curvature, whichmay, for example, becenter Cat. A line is then 'drawn from center Cza through the point on line L8 intersected by the arc. .The angle 5 then lies' between'the line so drawn and line Ls. As this angle is greater than the original angle formed between lines L2 and La, the Value of R as-determined' Icy Formula 1- will be correspondinglyreduced. In Formulae l and 2, the value of the torque input Ti is-assumed to be Titan 0, becomes larger, so that the net resultant Rr is decreased and Tr iscorrespondingly de-- creased. In determining Tr by-Formula 3,.the value of ,8 must remain constant, regardlessof the location of the center of the pivot'sockets in the connectors. Accordingly, moving th'e'centers of the pivot sockets inwardly hasthe'same effect as decreasing angle a.

The differential illustrated iniFigs. 1 and 11 includes a pair of driven members, each; of which has two intersecting circular grooves opening toward the driving "member between the driven members, and the "driving member has four radial slots. With such"aconstruction," the dif-' ferential is balanced in 9 action, as is made clear in the diagrams, Fig. 9. The driving member transmits power to the driven members only through slides lying in line with aligned intersections of the grooves in the two driven members and through the connectors engaged by those slides, the other slides and connectors being in- .efiective. When the driven members lie with their grooves in registry as shown in Fig. 9a, the driving member transmits power to the driven members through the two slides A and B in the vertical slots in the driving member and the slides in the horizontal slots are idle. When the driven member shown in Fig. 9 as free to rotate has moved angularly, so that the line through the centers of its grooves is displaced from the line through the centers of the grooves of the restrained driven member, power is transmitted through all four slides and their related connectors from the driving member to the driven member, since, with the driven members relatively displaced as described, all four slides lie in line with aligned intersections of the grooves in the two members. 91), in which the driven members are relatively displaced through 90.

It will be apparent from the foregoing that, if the driven members have two grooves and the driving member has two slots, the slots must be at right angles to each other, in order that the differential will function. However, with such a driving member, a condition will occur, when the slide in one slot is transmitting power from the driving member to the driven member free to rotate and the slide in the other slot is not transmitting power. At this instant, power will be wholly transmitted through a single slide and its connectors and the action will be unbalanced. If the driving member were provided with two slots lying aligned, the differential would not function, because the slides would be ineffective to transmit power, when aligned with the lines through the centers of the grooves of the driven members. If the driving member in a differential of the two-groove type were provided with three slots, the same unbalanced action described above in connection with a driving member having two slots would occur at certain stages in the operation. Accordingly, while the differential will function, when the driving member has only as many slots as there are grooves in each driven member or less than twice the number of grooves, balanced operation requires that the driving member have twice as many slots as there are grooves in a driven member.

Instead of providing each driven member with two intersecting circular grooves, it is possible to employ three grooves and the action occurring in such a differential is'diagrammatically illustrated in Fig. 8. In that figure, the circles 53 represent aligned grooves in the two driven members and the centers 54, 55, 56 of the grooves lie equally spaced from and equiangularly spaced about the axis of rotation A. The lines 51 radiating from axis A represent slots in the driving member. The solid arcuate lines '58 represent connectors of a set lying between the driving member and one driven member, and the dotted arcuate lines .59 represent connectors of the set lying between the driving member and the other driven member. The connectors 58, 59 are connected to slides, and, at each of'the aligned intersections to of the grooves in the two driven members, the slide is connected to a connector 58 and a connector 59 having ribs entering non-registering grooves in the two driven members,

This is apparent from Fig.

The three-groove differential shown in Fig. 8 functions in the same manner as the other forms of differential except that, as a minimum and as shown in Fig. 8, three slides are effective to transmit power from the driving member to the driven'members. With such a division of the load, the slides and connectors may be of somewhat lighter construction than Would be necessary in a two-groove differential for carrying the same load. If desired, the driven members may have more than three grooves and, in a form of the differential in which the driven members have four grooves, the centers of the grooves are apart and equally spaced from and about the axis of rotation. Any advantage to be gained by using driven members with more than three grooves would probably be overbalanced by the disadvantage of the complexities of the construction and, for most purposes, the differential has driven members provided with two grooves, as shown in Figs. 1 andll.

I claim:

1. In a differential, the combination of a pair of driven members mounted for coaxial rotation, each member having a plurality of intersecting circular grooves in its face opposed to the other member, the grooves all having the same radius and the centers of curvatureof all the grooves being equally spaced from and equiangularly spaced about the common axis of rotation of the members, a driving member coaxial with and between the driven members and having a plurality of angularly spaced radial slots, the number of slots being at least equal to the number of grooves in a driven member, a slide mounted in each slot and having portions exposed on opposite sides of the driving member, and a set of connectors between each driven member and the driving member and mounted for sliding movement in grooves in the adjacent driven member, each set consisting of a connector for each slide connected to the slide for rocking movement relative thereto, each slide lying in line with aligned intersections of grooves in the two driven members being connected to a pair of connectors mounted for sliding movement in non-registering grooves in the respective members.

2. In a differential, the combination of apair of driven members mounted for coaxial rotation, each member having a plurality of intersecting circular grooves in its face opposed to the other member, the grooves all having the same radius and the centers of curvature of all the grooves being equally spaced from, and equiangularly spaced about the common axis of rotation of the members, driving member coaxial with and between the driven members and having a plurality of equiangularly spaced radial slots, the number of slots being twice the number of grooves in a driven member, a slide mounted in each slot and having portions exposed on opposite sides of the driving member, and a set of connectors between each driven member and the driving member and mounted for sliding movement in grooves in the adjacent driven member, each set Y consisting of a connector. for each slide connected tothe slide for rocking movement relative thereto, each slide lying in line with aligned intersections of grooves in the two driven members being connected to a pair of connectors'mounted for sliding movement in non-registering grooves in therespective-members. a

3. In a differential, the combination of a pair of driven members, each member including a disc having a plurality of intersecting circular grooves in one face and" the members being mounted for coaxial rotation'with their grooved faces opposed, the'grooves in the discsbeing all of the same radius "and the centers of curvature of the grooves all being'equally spaced from and equiangularly spaced about the common axis of rotation ofthe members, a driving member coaxial with and between the discs and having a plurality of angularly spaced radial slots, the number of slots being at least equal to the number of grooves in a driven member, a slide mounted in each slot and havingiportions exposed on opposite sides of the driving member, and a set of connectors between each driven member and the driving'member and mounted for sliding movement in th'e'grooves in the adjacent driven member, each set consisting'of aconnectorfor each slide connected tothe slide for rocking movement relative thereto, each slide lying in line with aligned intersections of grooves'in the two driven members being connected to a' pair of connectors mounted for sliding movement in non-registering grooves in the respective members.

4. In a difierential, thecombination of a'pair of driven members mounted for coaxial rotation, each member having a fiat radial face formed with a pair of intersecting circular grooves, the grooves in the members being all of the same radius and the centers of curvature of the grooves in each member lying on a diameter of the member on opposite sides of the axis of rotation with all said centers lying equally spaced from said axis, the members being disposed with their grooved faces opposed, a driving member coaxial with and between the driven members and having four equiangularly spaced radial slots, a slide mounted in each slot and having portions exposed on opposite sides of the driving member,

and a set of connectors between each driven member and the driving member and mounted for sliding movement in grooves in the adjacent driven member, each set consisting of a connector for each slide connected to the slide for rocking movement relative thereto, each slide lying in line with alignedintersections of grooves in the two driven members being connected to a pair of connectors mounted for sliding movement in non-registering grooves in the respective members.

5. In a differential, the combinaion of a pair of driven members mounted for coaxial rotation, each member having a flat radial face formed with three intersecting circular grooves, the grooves in the member being all of the same radius and all the centers of curvature of the grooves in the members being equally spaced from and equiangularly spaced about the common axis of rotation of the members, a driving member coaxial with and between the driven members and having six equiangularly spaced radial slots, a slide mounted ineach slot and having portions exposed on opposite sidesof the driving member, and a set of connectors between each driven member and the: driving member and mounted for'sliding movement in grooves in the adjacent'driven member, each set consisting of a connector for each slide connected to the slide for rocking movement relative thereto, each slide lying in line with aligned intersections oi grooves in the two driven members being connected to a pair of connectors mounted for sliding movement in non=registering= grooves in the respective members.

6. In a differential, the-combination of a pair of driven members mounted for coaxial rotation, eachmemberhaving means for attachment to an element to be driven thereby, each member having a surface'formed with a plurality of intersecting circular grooves lying in a plane normal to the axis of rotation'of the member, the members havingthe same number of grooves and being disposed with the grooves in one member opening toward those in the other, all the grooves in the members being of the same radius and having their centers of curvature equally spaced from and equiangularly spaced about the common axis of rotation of the members, a driving member between the driven members, means for supporting the driving member for coaxial rotation with the driven members, the driving member having a' plurality of angularly spaced radial slots, the number of slots being at least equal to the number of grooves in a driven memher, a slidemounted in each slot and having portions. exposed on opposite sides of the driving member, and a set of connectors between each driven member and the driving member and mounted for slid-ingmovement in grooves in the adjacent driven member, each set consisting of a connector for each slide connected to the slide for rocking movement relative thereto, each slide lying in'line with aligned intersections of grooves in the two driven members being connected to a pair of connectors mounted for sliding movement in non-registering grooves in the respective members.

7. In a differential, the combination of a pair of driven members mounted for coaxial rotation, each member including a disc and an axial hub, the members being mounted with the faces of their discs opposed to each other and said faces each being formed with a plurality of intersecting circular grooves, the grooves all having the same radius and the centers of curvature of all the grooves lying equally spaced from and equiangularly spaced about the axis of rotation of the driven members, a driving member between the driven members, means for supporting the driving member for coaxial rotation with the driven members, the driving member having a plurality of angularly spaced radial slots, the number of slots being at least equal to the number of grooves in a' driven member, a slide mounted in each slot and having portions exposed on opposite sides of the driving member, and a set of'connectors between each driven member and the drivingmember and mounted for sliding movement in, grooves in the adjacent driven member, each set consisting of a connector for each slide connected to' the slide for rocking movement relative thereto; each slide lying in line with alignedintersections of grooves in the two driven members beingconnected to a pair of connectors mounted for sliding movement in nonregistering groovesv in the respective members.

8. In a differential, the combination of a pair of driven members mounted forcoaxial rotation, each member.v including adiscandan axial hub, themembers being mounted with the faces of their discs opposed toeachother and said faces each being, formedwith a plurality of intersecting circular grooves, thegrooves all having the same radius and the. centers of curvature of all the grooves lying equally spaced from and equiangularly spaced about the axis of rotation of the driven members, a driving member between the driven members, a: supporting member mounted for; coaxial. rotation with the driven members and engaging the driving member and supporting it for coaxial rotation with the driven members, the driving member having a plurality of angularly spaced radial slots, the number of slots being at least equal to the number of grooves in a, driven member, a slide mounted in each slot and having portions exposed on opposite sides of the driving member, and a set of connectors between each driven member and the driving member and mounted for sliding movement in grooves in the adjacent driven member, each set consisting of a connector for each slide connected to the slide for rocking movement relative thereto, each slide lying in line with aligned intersections of grooves in the two driven members being connected to a pair of connectors mounted for sliding movement in non-registering grooves in the respective members.

9. In a differential, the combination of a pair of driven members mounted for coaxial rotation, each member having a central socket and a plurality of intersecting circular grooves in its face opposed to the other member, the grooves all having the same radius and the centers of curvature of all the grooves being equally spaced from and equiangularly spaced about the common axis of rotation of the members, a driving member between the driven members, the driving member having projections from its opposite sides received in the sockets in the driven members and supporting the driving member for coaxial rotation with the driven members, the driving member having a plurality of angularly spaced radial slots, the number of slots being at least equal to the number of grooves in a driven member, a slide mounted in each slot and having portions exposed on opposite sides of the driving member, and a set of connectors between each driven member and the driving member and mounted for sliding movement in grooves in the adjacent driven member, each set consisting of a connector for each slide connected to the slide for rocking movement rela tive thereto, each slide lying in line with aligned intersections of grooves in the two driven members being connected to a pair of connectors mounted for sliding movement in non-registering grooves in the respective members.

10. In a differential, the combination of a pair of driven members mounted for coaxial rotation, each member having a plurality of intersecting circular grooves in its face opposed to the other member, the grooves all having the same radius and the centers of curvature of all the grooves being equally spaced from and equiangularly spaced about the common axis of rotation of the members, a driving member coaxial with and between the driven members and having a plurality of angularly spaced radial slots, the number of slots being at least equal to the number of grooves in a driven member, means attached to the driving member for rotating it, a slide mounted in each slot in the driving member and having portions exposed on opposite sides of the driving member, anda set of connectors between each driven member and the driving member and mounted for sliding movement in grooves in the adjacent driven member, each set consisting of a connector for each slide connected to the slide for rocking movement relative thereto, each slide lying in line with aligned intersections of grooves in the two driven members being connected to a pair of connectors mounted for sliding movement in non-registering grooves in the respective members.

11. In a differential, the combination of a pair of driven members mounted for coaxial rotation, each member having a plurality of intersecting circular grooves in its face opposed to the other member, the grooves all having the same radius and the centers of curvature of all the grooves being equally spaced from and equiangularly spaced about the common axis of rotation of the members, a driving member mounted for rotation coaxially with and between the driven members and having a plurality of angularly spaced radial slots extending through it, the number of slots being at least equal to the number of grooves in a driven member, and a plurality of assemblies, one for each slot in the driving member, having portions mounted in respective slots for sliding movement, each assembly having other parts slidably entering a pair of grooves, one in each driven member, each groove receiving at least one part of an assembly and each assembly lying in line with aligned intersections of grooves in the two driven members having parts entering non-registering grooves, one in each member, in the respective driven members.

12. In a difierential, the combination of a pair of driven members mounted for coaxial rotation, each member having a plurality of intersecting circular grooves in its face opposed to the other member, the grooves all having the same radius and the centers of curvature of all the grooves being equally spaced from and equiangularly spaced about the common axis of rotation of the members, a driving member mounted for rotation coaxially with and between the driven members and having a plurality of angularly spaced radial slots extending through it, the number of slots being twice the number of grooves in a driven member, and a plurality of assemblies, one for each slot in the driving member, having portions mounted in respective slots for sliding movement, each assembly having other parts slidably entering a pair of grooves, one in each driven member, each groove receiving at least one part of an assembly and each assembly lying in line with aligned intersections of grooves in the two driven members having parts entering non-registering grooves, one in each member, in the respective driven members.

DONALD E. SCHOTT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,355,170 Seeck Oct. 12, 1920 1,505,570 Levin Aug. 19, 1924 1,626,120 Seeck Apr. 26, 1927 1,934,721 Lawler Nov. 14, 1935 FOREIGN PATENTS Number Country Date 26,023 Sweden Dec. 12, 1908 

